The present invention generally relates to combustion technology and, more specifically, sealing configurations between rotating and stationary components within the hot gas path of the combustion turbine.
Typically, a near-flow-path seal is located between adjacent stages of buckets just below the neighboring nozzle. More specifically, the near-flow-path seal is loaded into a spacer wheel or disk located axially between adjacent wheels or disks that support peripheral rows of turbine buckets. The near-flow-path seal has arms that extend axially in opposite directions from the spacer wheel dovetail to form a flow path below the nozzle and to keep hot combustion gases out of the radially inner wheel space. The axial arms of the near-flow-path seal are not self-supported, however, and each requires a loading surface when the turbine is under normal operation and exposed to centrifugal forces exerted as the turbine rotor rotates. In a typical configuration, the near-flow-path seal is loaded at three points: on the spacer wheel located between the neighboring wheels through a dovetail; and on loading surfaces of the two adjacent buckets, typically surfaces of the integral cover plates on the respective buckets.
There remains a need, therefore, for a near-flow-path seal design that ameliorates the loading (e.g., centrifugal and/or axial) into the adjacent buckets.